PK parameters exam 1

Co definition

concentration at time 0
drug concentration in plasma at time 0

Co clinical significance

used to calculate volume of distribution

k, definition

proportionality constant which relates elimination rate to amount
fractional rate of drug removal

k, clinical significance

allows determination of how long drug is in body for and how often to dose the patient

t1/2, definition

time required for drug concentration in body to decline by half

t1/2, clinical significance

indicator for speed of elimination
indicates time for appropriate follow up doses

AUC, definition

measurement of the extent of absorption

AUC, clinical significance

allows for calculations of bioavailability

Vd, definition

proportionality constant relating amount and concentration

Vd, clinical significance

reflects the extent of distribution in the body
allows calculation of loading doses

Blood volume

4.5-5L

Plasma volume

3L

Extracellular water

15L

Intracellular water

27L

CL, definition

proportionality constant relating elimination rate to concentration

CL, clinical significance

determination of organ function
design of dosing regimens

CLr, definition

proportionality constant relating excretion rate to concentration

elimination rate constant variable

k

disposition rate constant variable

β

biological half life variable

t1/2β

terminal half life variable

t1/2β

physical half life variable

t1/2β

distribution rate constant

α

distribution half life

t1/2α

Vc, Vi, Vp, definition

relates initial amount of drug in body to initial concentration in central compartment

Vc, Vi, Vp, clinical significance

calculations of loading dose

Vdss, definition

relates concentration to amount of drug in body at steady state

Vdss, clinical significance

calculations of loading dose